The Edge Monitoring System is a method by which manufacture of a workpiece can be controlled by a system having architecture comprising modular hardware and modular software. Signals are detected from the manufacturing process and transmitted to the system by the modular hardware. The signals are then processed by the modular software for detecting specific features or patterns in these signals to control the manufacturing process.
Illustrative of an example of the type of modular hardware is that described in commonly assigned U.S. Pat. No. 4,806,914 for Detection by Automatic Gain Control Features of Gradual Cutting Tool Breakage. This application describes several tool monitoring patents. Each of these devices has employed an analysis of signals, specifically vibration signals produced when machining a workpiece in order to detect a tool break.
Examples of these devices include a tool monitor based upon a high frequency vibration signal, a tool monitor based upon an acoustic emission sensor, a tool monitor based upon three-axis force transducers, a tool monitor based upon strain sensors, or a tool monitor based upon a spindle power sensor. Each of these devices is specific to a single type of sensor. All of these devices are particularly designed for a specific machining operation. None of these devices have the capability of controlling a variety of different tooling operations because each is designed for its particular tooling procedure.
Illustrative of examples of systems with objectives similar to the applicants are those disclosed in a paper by F. Z. Shen et al. published in the proceedings of the 1989 North American Manufacturing Research Conference (NAMRC) and in a paper by F. Richter and S. A. Spiewak also published in the 1989 NAMRC proceedings. However, both of these systems employ an architecture substantially different for that of the applicants. The former paper discloses a system wherein each monitoring algorithm runs on a separate CPU board each having a separate A/D interface. In the latter paper, a system is described wherein their Modular Multi-Processor System has only a single type of signal.
None of the above-described systems teach or disclose the system taught by the applicants. The Edge System is fully integrated, and all algorithms share the same A/D, serial, and Ethernet interface. Further, the software may be arbitrarily distributed across one or multiple CPU's in the Edge System. Additionally, unlike the system described by Richter and Spiewak, the Edge System architecture specifies a uniform interface for signal processing algorithms and Edge's Ethernet interface provides diagnostic capabilities.
The productivity of modern manufacturing operations is limited by the availability of powerful and flexible process monitoring systems. If a machine which is manufacturing a workpiece fails and is not detected, expensive parts and machine tools can be damaged. In the absence of an effective monitoring system, process conditions must, of necessity, be conservative to minimize the risk of machine failure.
Existing tool monitoring systems are narrowly designed, typically around a single type of sensor as described above. While each is appropriate with varying degrees of effectiveness in a narrow range of applications, none are fully effective in a flexible manufacturing system comprising a variety of machining operations. For example, none of the systems described by the prior art is, by itself, capable of controlling milling, drilling, turning and other machining processes. Thus, no single system exists which can control a wide range of machining operations.